The surprising truth about bird brains, monkey minds, and more

    Scrub jays can trick you, researchers say. Monkeys kick themselves for mistakes in judgment. And at least one parrot figured out something close to the mathematical concept of zero.

    Animals can be remarkably devoted-as the stories on these pages prove. What's less obvious is how smart they are. In study after study over the past decade, they've shown abilities previously thought to exist only in humans.

    Take the scrub jays. A few years ago, Cambridge University professor Nicky Clayton, PhD, found that these birds can be surprisingly devious, remembering not only what foods they've hidden but where, how long ago, and whether anyone else might have noticed. "If another bird was watching, they'd wait until that bird was gone and then move the food," Clayton says.

    Even more interesting, not all jays protected their food that way-only those that had previously raided other birds' stores. "It takes a thief to know a thief," says Clayton. Another recent experiment hints that monkeys experience regret when they make the wrong choice and miss out on a treat: Researchers say brain scans suggest the animals were having "coulda, woulda, shoulda" thoughts.

    "I knew monkeys were smart, but I didn't think they were that smart," says Michael Platt, PhD, the Duke University neurobiologist who led the study.

    But perhaps no animal has done more to upend conventional notions than Alex, an African gray parrot. A 30-year research subject for scientist Irene Pepperberg, PhD, Alex whittled away at the belief that parrots were simple mimics. He was constantly being tested; when he tired of it, he would tell Pepperberg, "Wanna go back"-to his cage. If the request annoyed her, Alex would say, "Sorry." The parrot toyed with her relentlessly, and one afternoon, he showed an apparent grasp of something only humans and a few apes had been known to understand: the notion of zero.

    Pepperberg had a tray of different-colored balls; she wanted Alex to count each group. Using their shorthand, she asked, "What color six? What color two?" Bored, Alex threw the balls on the floor instead. Then, finally, he said, "Five." And repeated it: "Five. Five." There were no five of anything on the tray. So Pepperberg asked, "Okay, smarty, what color five?"

    Alex said, "None."

    Not only had the bird figured out an abstract mathematical concept, he had manipulated Pepperberg into asking the question so he could prove it. "I nearly dropped the tray," she says.

    關于鳥類大腦，猴子思維以及更多的驚人真相

    研究者發現，灌木叢里的鳥兒也能把你騙到。猴子會因為自己判斷失誤而自我懲罰。至少已經有一只鸚鵡能夠理解一些與"0"相近的數學概念。

    動物可以非常忠誠--正如這些網頁上的故事所證實的那樣。但是它們的聰明伶俐就不是那么顯而易見的了。過去十年間，一項又一項研究表明，動物表現出過去認為只有人類才具有的能力。

    這里以灌木叢鳥作為例子。幾年以前，哥倫比亞大學教授，Nicky Clayton發現這些鳥兒驚人的狡猾，它們不僅能記住自己藏了什么食物，而且記得何時，多久以前，是否會被其它動物發現。"如果被其它鳥兒看著，它們會耐心等待，直到那鳥兒飛走它們才會搬動食物。" Clayton 說。

    更為有趣的是，不是所有的鳥都用這種方法保護它們的食物--只有那些曾經偷吃其它鳥的食物的鳥才會這樣。"最了解小偷的人就是小偷。"Clayton說。另一個最新的實驗則啟示我們，猴子在因為自己錯誤的選擇而錯失食物后會感到后悔：研究者聲稱，腦掃描表明猴子們有"本可以，本來會，本應該"的想法。

    "我知道猴子聰明，但我沒想到它們是如此聰明。" 杜克大學的神經生物學教授Michael Platt說，他是上述研究的負責人。

    但是，或許沒有其它動物比Alex,一只非洲灰鸚鵡，更加顛覆了傳統觀念。對于科學家Irene Pepperberg博士來說，Alex,這只30歲的實驗對象削弱了"鸚鵡只是簡單的模仿生物"這一觀念。Alex不斷接受實驗，當它厭倦時，它會告訴 Pepperberg博士："想要回去"--回到它的籠子里。如果實驗要求令它不高興了，Alex會說："對不起。"這只鸚鵡無所顧忌地與博士玩耍。一天下午，Alex表現出只有人類和少數猩猩才擁有的理解力：0的概念。

    Pepperberg博士拿來一個盛著不同顏色的球的盤子。她要求 Alex數出每種顏色的球有多少個。Pepperberg博士用很短的句子提問："什么顏色有6個？什么顏色有2個？"Alex把球丟起來扔到地上，感到厭煩。最后，它說："5."之后一再重復："5,5."盤子上并沒有5個同樣顏色的球。于是Pepperberg博士問到："好的，你很聰明，什么顏色有5個？"

    Alex 回答說："沒有。"

    Alex不僅理解了抽象的數學概念，而且還引導Pepperberg博士問出問題，好讓它來解答。 "我幾乎把盤子摔在了地上。" Pepperberg博士說。